1. Field of the Invention
The present invention relates to a device for sterilization by ultraviolet radiation, comprising a UV radiator arranged in a housing made of metal or plastic, which has a radiation outlet window for emitting UV radiation covered by a polymer film that is transparent for ultraviolet radiation.
2. Prior Art
UV radiators are used for sterilization, for example in air-conditioning and drinking water systems, as well as in food production. Here, both food, such as fruit and vegetables, and also machine parts, packaging materials, liquids, air and surfaces that come in contact with the food during its preparation are irradiated. The UV radiators are typically surrounded by a quartz glass jacket tube and can be arranged in the direct vicinity of or at a greater distance from the goods to be irradiated, for example as an overhead fitting for air and surface sterilization. One disadvantage is that, if the quartz glass jacket tube breaks, fragments can get into or onto the goods to be irradiated. To prevent this, a plurality of safety devices are known that require, however, a certain amount of expense in terms of measures and materials.
This disadvantage is avoided by a sterilization device of the type mentioned at the outset, as known, for example, from German published patent application DE 10 2005 026 645 A1. Therein it is proposed to hold the UV radiator surrounded by a quartz glass jacket tube in a cylindrical metal or plastic housing equipped with a radiation outlet window for emitting UV radiation. A film made of a fluoropolymer (MFA) is shrunk-fit over the housing and the radiation outlet window. This film has a high degree of transparency for radiation with wavelengths around 253.7 nm.